Valve stem grinder



Jan. 3, 1939. J. M. KROHN VALVE STEM GR1NDE-R 2 sneetsfs'heet 1 Filed Aprill 5, 1955 VENT. R

ToRNEY Jam-3, 1939. J M KROHN 27,142,565

. l VALVE STEM GRINDER Filed April 5, 1935 2 Sheets-Sheet 2 ATTORN EY Patented Jan. 3, 1939 UNIT-ED STATESy PAT ENT OFFICE 14 Claims.

This invention relates to grinding machines which are particularly adapted to grind the excess length from rods such as valve stems.

When the valves of an automobile are ground an adjustment must be made to the length of the valve stem. Where the stem is not adjustable as in the case of the cars manufactured by the Ford Motor Car Company, the end of the valve stem must be ground off. When this is done the mechanic measures the amount to be ground off with a feeler gage and grinds it by hand, estimating when he has ground off enough, and ts it by a cut and try method.

One object of this invention is to produce a valve stem grinder which may be set to grind off the necessary amount of the valve stem while rotating the stern and which will cease the grinding when the stem is the proper length.

Another object is to produce a valve stem grinder having an improved valve holder which rotates the stem While grinding.

Further objects are to produce a valve stem grinder which is simple to use and which will reduce the time and labor and increase the accuracy of setting the valve,

Other objects will become apparent upon consideration of the following specification.

In the drawings:

Fig. 1 is a horizontal cross-section of a valve stem grinder embodying the principles of the invention, and is a cross-section on the line I-l of Fig. 2.

Fig. 2 is an end elevation of the grinder shown in Fig. 1 with parts broken away on the lines 2-2' and 2"-2" of Fig. 1.

Figs. 3, 4 and 5 are cross-sections on the lines 3--3, 4 4 and 5 5 respectively, of Fig. 1, looking in the direction ofthe arrows.

Referring to the drawings, in which like numerals indicate like parts throughout the severalviews, the grinder is shown mounted on a base I0 with a motor driven emery wheel Il, a holding and feeding mechanism generally designated l2 and a valve stem guide I3.

The emery wheel Il is driven by a motor l5, with a shaft I8 projecting through the stone ll and secured thereto by a Vnut I1, which screws into a recess i8 in the stone. A facing tool 20 slidably mounted in a standard 2l maintains the grinding face of the stone perpendicular to the motor shaft and the stem of a valve 23 which is being ground.

The holding and feeding mechanism which has been designated I2 is mounted in and on a housing., 25which has a cover plate 26 closing the rear of the housing. The housing 25has a bearing 21 which rotatablyv receives and guides a spindle or feeding head 28. The head 28 has one or more recesses 29 formed therein, as shown in Figs. 1 and 3, which receive the headl of the valve 23 while the stem of the valve is'held and guided by the valve stem guide I3. A bolt I3 is threaded through the head from the end opposite the recesses. 23 and engages the head ofthe valve to hold it in place whileitis beingV fedinto the grinding wheel.

The outer end of the spindle or feeding head 28 projects through an elongated opening 30 in the cover plate 26, as shown in Fig. 3, which permits the valve head toI enter the housing 25 and be inserted in a slot 3| in the feeding head 28.

A gear 32 is formed ontlrie.l head 28, which is rotated by a driving gear 33. The gear 33 has annular plates 3i.-3llf fixed on its sides which project past the outer edge of the gear teeth and engage the sidesy of the gear 32 so that axial movement of the gear 33 is transmitted directly to the gear 32 and causes a corresponding movement of the head 28.

The gear 3 3 is formed cna shaft 35 which is mounted ina bearing4 36 in the housing 25. The shaft 35` isturnedby a handle 31 outside the housing 25.

The end of shaft 35 opposite the handle 31 is provided with a cylindrical bore 38 which terminates in a co-axial threaded hole 39. A piston dil fits into the cylinder 38 and forms a guide for that end of the shaft 35. The piston has a co-axial screw 4l thereon which engages with the threads in the opening 39 to advance the gear 33 in the housing25.

The piston 4E), is held fixed in a standardk 42 and isl held against rotation therein by al key 43and againstv axial movement by a nut 44.

As the shaft 35; is,v rotated through the handle 31 the screw ll engages, the threads in the hole 39 and causes a, corresponding linealmovement of the gear 3 3which transmits the same lineal` movement to thegear 32 through the annular plates Sil-3 4, The, axial movement of the head, 284 depends on the pitch of the` screw 4l. If, for example, that screw contains `twenty iive threads per inch, each fullturn of the handle 31 advancesthe head 2.8four hundredths of an inch, and portions of a turn advance the head in proportion.

A dividing head, generally designated 43.', is mounted on ,the housing 25 surrounding the feed,- ing head 28, andris. adapted to limit the rotation of the head 28 to a predetermined angle in the manner described below.

The dividing head 43 has an annular ring 45 fixed to the housing 25 concentrically with the head 28. The ring 45 has an annular recess formed on the inside surface adjacent the housing 25, which rotatably receives an annular projection or ange 46 on a cylinder 41 the member 46-41 constituting a dividing plate. The flange has a plurality of holes 48 at equal intervals about the periphery which are adapted to be engaged by a spring pressed plunger 48. The number of holes is a matter of convenience. ple, if one revolution of the head 28 advanced it four one hundredths as in the above example, forty holes would permit the valve stem to be ground to one thousandth of an inch.

The interior of the cylinder 41 receives a collar' 50 which abuts against a shoulder 5l on the tail end of the feeding head 28 and is adapted to beheld against movement relative to the feeding head by a pair of nuts 52 threaded on an extension 53. The collar 50 carries a spring pressed plunger 54, which is adapted to engage a stop hole 55 and stop the rotation of the feeding head 28.

Theplunger is adapted to be held out of engagement with the hole 55 by a pin 56 which normally fits in a slot 51 in the collar 50 and which engages the outer edge of the collar when the plunger is withdrawn from the cylinder and turned at right angles.

A handle 58 is provided on the cylinder 41 to facilitate the turning thereof, and a pointer 5B indicates on a scale 60 on the ring 45, the setting of the plunger 4B,

Operation In operation, after the amount to be ground olf the valve stem has been determined by a feeler gage, the valve stem is secured in the valve guide I3 with the valve head in one slot 29. 'I'he bolt I9 is screwed down on the head of the valve and secured against loosening by the lock nut. The nuts 52 may then be loosened which disengages the dividing head 43'. The handle 31 is turned to advance the shaft 35 on the screw 4I, which advances the feeding head 28 until the end of The nuts feeding head 28. The plunger 54 is then withdrawn from the port 55 and held out of engage- -ment by turning the handle until the pin 56 rests on the outer edge of the collar 50. The plunger 48' is withdrawn from the port 48 and the cylinder 41 rotated until the indicator 59 shows the desired cut on the scale 60.

AMoving the cylinder moves the port 55 out of alinement with the plunger 54. Both plungers 48 and 54 may then be released. The plunger 48' engages in a port 48 while the plunger 54 rides on the plate forming the inner end of the cylinder 41. The valve stem is ground by turning the handle 31 which advances the stem onto the rotating stone H. When the required amount has been removed, the plunger 54 again comes into alinement with the port 55, and permits the spring 53' to engage the plunger 54 in the port 55 and stop further rotation of the stem.

It is realized that this invention is susceptible to various changes and modifications and it is not, therefore, desired to limit the invention to the precise form herein shown and described but only by the scope of the appended claims.

For exam-A said member, and means to transmit said rotation and said advancing movement to said feed ing head whereby the stem of the valve is advanced onto said stone to be ground.

2. A valve .stem grinder of the character described comprising, a base, a grinding stone mounted on the base and adapted to grind a valve stem, a feeding head adapted to hold the valve and feed the stem onto the stone, a screw adapted to advance the feeding head while the head is being rotated, a dividing head surrounding the feeding head, and means to releasably secure the dividing head to the feeding head.

3. In a grinder of the character described, a base, a standard mounted on said base, said base and said standard constituting a fixed member, a spindle mounted for rotational movement in said standard, a dividing plate mounted to rotate about said spindle, said plate having a plurality of apertures therein, a stop member mounted on said fixed member and engageable with certain of said apertures, and a second stop member rotatable with said spindle and engageable with another of said apertures to limit the rotational movement of said spindle.

4. In a grinder of the character described, a base, a standard mounted on said base, said standard and said base constituting a fixed member, a spindle mounted for rotational and axial movement in said standard, means to move said spindle axially in proportion to the rotation thereof, a dividing plate mounted to rotate about said spindle, said plate having a plurality of apertures therein, a stop member mounted on said xed member and engageable with certain of said apertures, and a second stop member rotat- M able with said spindle and engageable with another of said apertures to limit the rotational movement of said spindle.

5. In a grinder of the character described, a base, a standard mounted on said base and constituting with said base a fixed member, a spindle mounted for rotational movement in said standard, means to hold a work piece in said spindle, a dividing plate mounted concentrically about said spindle and adapted to rotate relative thereto, said plate having a plurality of first named apertures arranged on a circumference thereof and a second named aperture spaced from said rst named apertures, a stop member mounted on said xed member and engageable with said first named apertures to fix the angular position of the plate, and a second stop member rotatable with said spindle and engageable with said second named aperture to limit the rotational movement of the spindle.

6. In a grinder of the character described, a base, a grinding stone mounted on said base, a standard mounted on said base, said base and said standard constituting a fixed member, a

spindle mounted for rotational and axial movement in said standard, means on said spindle to hold a work piece, means to move said spindle axially inproportion to the rotation thereof, a dividing plate mounted concentrically about said spindle and adapted to rotate relative thereto, 75

said plate having a plurality of first namedapertures arranged on acircumference thereof and a second named aperture spaced from said first named apertures, a stop member mounted on said fixed member and engageable With said first named apertures to fix the angular position of the plate, and a second stop member rotatable with said spindle and kengageable with said second named aperture to limit the rotational movement of the spindle.

7. In a grinder of the character described, a base, a grinding stone mounted on said base, a standard mounted on said base, said base and said standard constituting a fixed member, a spindle mounted for rotational and axial movement in said standard, means on said spindle to hold a Work piece, a screw drive adapted to advance the spindle in proportion to the rotation thereof, a dividing plate mounted concentrically about said spindle and adapted to rotate relative thereto, said plate having a plurality of first named apertures arranged on a circumference thereof and a second named aperture spaced radially inward from said first named apertures, a stop member mounted from said fixed member and engageable with said rst named apertures to fix the angular position of the plate, and a second stop member rotatable with said spindle and engageable with said second named aperture to limit the rotational movement of the spindle.

8. In a grinder of the character described, a base, a standard mounted on said base and constituting With said base a fixed member, a spindle mounted for rotational movement in said standard, means on said spindle to hold a Work piece to be ground, a dividing plate mounted to rotate about said spindle, said plate having a plurality of apertures therein, a stop member mounted on said fixed member and engageable with certain of said apertures to limit the rotational movement of the plate, a support releasably secured on said spindle, and a second stop member carried by said support and engageable with one of said apertures to limit the rotational movement of the spindle.

9. In a grinder of the character described, a base, a standard mounted on said base and constituting with said base a fixed member, a spindle mounted for rotational and axial movement in said standard, means to move said spindle axially in proportion to the rotation thereof, a dividing plate mounted to rotate about said spindle, said plate having a plurality of apertures therein, a stop member mounted on said fixed member and engageable with certain of said apertures to limit the rotational movement of the plate, a support releasably secured on said spindle, and a second stop member carried by said support and engageable With one of said apertures to limit the rotational movement of said spindle.

10. In a grinder of the character described, a base, a standard mounted on said base and constituting With said base a fixed member, a spindle mounted for rotational movement in said standard, means for holding a Work piece in said spindle, a dividing plate mounted concentrically about said spindle and adapted to rotate relatively thereto, said plate having a plurality of first named apertures arranged on a circumference thereof and a second aperture spaced from said other apertures, a stop member mounted on said xed member and engageable with said first named apertures to fix the angular position of the plate, a support releasably secured to said spindle, and a second stop member carried by said support and engageable with said second named aperture to limit the angular movement of said spindle.

11. In a grinder of the character described, a base, a grinding stone mounted on said base, a standard mounted on said base, said base and said standard constituting a fixed member, a spindle mounted for rotational and axial movement in said standard, means on said spindle to hold a Work piece, means to move said spindle axially in proportion to the rotation thereof, a dividing plate mounted concentrically about said spindle and adapted to rotate relative thereto, said plate having a plurality of first named apertures arranged on a circumference thereof and a second named aperture spaced from said first named apertures, a stop member mounted on said fixed member and engageable with said first named apertures to fix the angular position of said plate, a support releasably secured to said spindle, and a second stop member carried by said support and engageable with said second named aperture to limit the rotational movement of the spindle.

12. In a grinder of the character described, a base, a grinding stone mounted on said base, a standard mounted on said base, said base and said standard constituting a fixed member, a spindle mounted for rotational and axial movement in said standard, means on said spindle to hold a Work piece, a screw drive adapted to advance the spindle in proportion to the rotation thereof, a dividing plate mounted concentrically about said spindle and adapted to rotate relative thereto, said plate having a pluraity of first named apertures arranged on a circumference thereof and a second aperture spaced radially inward from said first named apertures, a stop member mounted from said fixed member and engageable with said first named apertures to fix the angular position of the plate, a support releasably fixed to said spindle, and a second stop member carried bysaid support and engageable with said second named aperture to limit the rotational movement of the plate and hence the grinding action.

13. In a grinder of the character described, a base, a standard mounted on said base and constituting With said base a fixed member, a grinding stone mounted on said base and spaced from said standard, a spindle mounted for rotational movement in said standard, means on said spindle to hold a Work piece, a dividing plate mounted to rotate about said spindle, said plate having a plurality of first named apertures arranged on a circumference in said plate, a cylindrical extension on said plate, said plate having a second named aperture therein Within said cylinder, a second cylinder mounted Within said first cylinder and on said spindle, means to releasably fix said second cylinder to said spindle to rotate therewith, a stop member mounted on said fixed member and engageable with said first named apertures to fix the angular position of said plate relative to said fixed member, and a second stop member carried by said second cylinder and engageable with said second named aperture to limit the angular movement of the spindle.

14. In a grinder of the character described, a base, a standard mounted on said base and constituting with said base a flxed member, a grinding stone mounted on said base and spaced from said standard, a spindle mounted for rotational and limited axial movement in said standard, screw impelling means adapted to effect axial movel0 which passes between the first and second named apertures, a second cylinder mounted within said irst` cylinder and on said spindle, means to releasably X said second cylinder to said spindle to rotate therewith, a stop member on said xed member engageable With said rst named apertures to x the angular position of said plate, and a second stop member carried by said second cylinder and engageable with said second named aperture to limit the rotation of the spindle.

JOHN M. KROHN. 10 

